Weakness is the feeling of body fatigue, or tiredness. A person experiencing weakness may not be able to move a certain part of their body properly. They may also experience tremors, which are uncontrollable movements, or twitches in the area of w...

Being tired is the familiar aftermath of physical exertion, prolonged labor or lack of sleep. When does being tired become a symptom of a condition? Fatigue, malaise, lassitude, exhaustion are all subtle variations of the same subjective feelings of not having enough energy to meet the demands of one's life.